What do you need to include in your donation acknowledgment letter? A donation acknowledgment letter (sometimes called a donation receipt or thankyou letter) is an email or paper that recognizes a charitable contribution.What to include in donor acknowledgment letters? Decide beforehand how much you can afford to donate to causes. Keep track of your charitable giving so you stay within your budget. Want to learn how to write and structure donor acknowledgment letters? Check out these tips and sample letters to make a greater impact. The easy answer: Yes, you may notarize out-of-state documents. All PDF forms and documents function optimally when downloaded to your computer and opened with the free Adobe Acrobat Reader software.